Elevator door control systems



Jan 25., 1966 o. E. MITCHELL 3,231,048

ELEVATOR DOOR CONTROL SYSTEMS Filed Sept. 18, 1963 United States Patent O 3,231,048 ELEVATOR DOOR CONTROL SYSTEMS Omery Edward Mitchell, Toronto, Ontario, Canada, as-

signor to Turnbull Elevator Limited, Toronto, Ontario, Canada, a corporation of Canada Filed Sept. 18, 1963, Ser. No. 309,792 7 Claims. (Cl. 187-51) This invention relates to elevator systems, and in particular to an arrangement for ensuring that obstruction of the hall door in an elevator system when the door is closing shall cause both the hall door and the car door to open.

In a typical passenger elevator system there is provided an elevator car having a car door reversibly movable between open and closed positions and reversible power means to open and close said door. At each hall in the building in which the elevator system is installed there is a hall door which is driven by the car door through interengaging elements on the doors. The car door is operated automatically and, in order that passengers attempting to enter or leave the car while the doors are closing may reverse the door motion, various types of protective devices are employed and are associated with the leading edge ofthe car door.

Such a protective `device may take the form of a resiliently mounted strip on the leading edge of the car door and arranged so that, when pressed by a passengers hand or by contact with a passengers body, it actuates a switch to open the doors. Another form of protective device is a photoelectric cell which is operated by the breaking of a light beam across the entrance to the car. Yet another protective device is a thyratron tube which is caused to conduct, and thus operate a circuit to open the doors, by capacitive coupling between a passengers body and a metal strip on the leading edge of the car door.

A passenger wishing tov leave the elevator car while the doors are closing can usually cause the doors to open by operating the protective device on the car door. Moreover, a button is generally provided in the car which may be operated to open the doors. On the other hand, a person wishing to enter the car while the doors are closing may not be able to reach the protective device on the car door, particularly since the hall door may conceal the protective device from view. Very often, therefore, a person wishing to enter the car as the doors are closing will be left behind unless a passenger in the car presses the control button to open the door or the person wishing to enter the car presses a button located in the hall to open the doors.

It would be possible to provide a protective device on each hall door similar to the'device provided on the car door. However, there are normally a multiplicity of hall doors, at least one at each floor of the building in which the elevator system is installed, and the provision of a protective device on each hall door is uneconomical and is not normally provided.

The object of this invention is to provide comparatively inexpensive means whereby the closing doors of an elevator car maybe caused to open when the hall door is obstructed.

The invention will now be described by way of example ywith reference to the accompanying drawings, in which,

FIGURE l is a diagrammatic horizontal section through an elevator car and a hall entrance showing the mechanical features of the invention, and

FIGURE 2 is a schematic circuit diagram of the electrical circuit used to carry out the invention, the relay contacts being shown in their normal positions, i.e. the lpositions they occupy when their associated relay coil is de-energised. i

Referring now to FIGURE l, the elevator car consists ice of side walls 10 and 11, a rear wall 12, a front wall 13 and an entrance 14. A car door 15 is slidably mounted on the car and is movable between open and closed positions by means of a motor 16 driving a crank 17 through a gear box 18; the crank is connected to the door 15 by a link 19. Parts of the building in which the elevator system is installed are indicated at 20 and dene between them a hall entrance 21. A hall door is indicated at 22 and is reversibly movable between the positions in which the entrance 21 is opened and closed.

A vertically extending strip 23 is slidably mounted adjacent to the leading edge 24 of the car door 15. The strip 23 is movable against the action of a spring 25 and is arranged to coact with a switch SD mounted on an abutment 26 secured to the car door. Should the car door encounter an obstruction during closing, the strip 23 is moved to the right in FIGURE l relative to the car door Iand operates the switch SD which, as will hereafter be described, causes the doors to open. The leading edge of the car door 24 coacts with an abutment 27 on the side wall 10 of the car when the door is shut.

Mounted on the side of the hall door 22 adjacent to the car door 15 is an element 28 of a pair of interengaging elements 2S and 29. The element 28 is in the form of a block with a vertically extending groove 30 in the face of the block adjacent the hall door 15, The element 29 is in the form of a vertically extending rib pivotally mounted to the car door at 31 and, as will be seen from FIGURE 1, the rib 29 is received within the groove 30 of the block 28. The door at each hallway in the building'is provided with a similar block 28 and, as the car moves up or down into register with the hallway entrance, the rib 29 will enter the corresponding groove 30 of the block 28 on the -hall door.

A stop 32 is provided for the rib 29 and the rib is forced against the stop by spring 33 which coacts at'its other end with an abutment 34. The engagement, under the influence of the spring 33, of the rib 29 with the element 28 biases the doors 15 and 22 to a normal relative position shown in FIGURE 1. The rib 29 coacts with ia lswitch CS mounted on the cardoor and normally the switch CS is closed vwhen the parts are in the positions shown in FIGURE 1. However, should the hall door be obstructed while closing, the resilient mounting of the rib 29 will permit a limited further closing movement of the car door from the normal relative position or the hall door will move to the right in FIGURE 1 relative to the car door. During' this further closing movement the rib 29 will pivot in an anticlockwise direction away from the stop 32 and, as a result, the switch CS will be caused to open and, as will hereafter be described, will thus cause the doors to open. j

Indicated diagrammatically in FIGURE 1 are mcchanically operated contacts indicated generally at 35. These contacts are operated mechanically by the car door in dependence on its position and include open limit contacts OL, open check contacts OC, close check contacts CC and close limit contacts CL all of which are shown in FIGURE 2. There is also included a set of contacts CA for a purpose hereinafter to be described.

Referring more particularly to FIGURE 2, in this iigure there is shown a door relay D having normally open contacts D1 and normally closed contacts D4. The circuit also includes a close relay C having normally open contacts C1 and C2 and normally closed contacts C4 and C5; and an open relay O having normally open contacts O1, O2 and O3 and normally closed contacts O4 and O5. The door motor 16 is shown as having an armature DMA and a continuously excited eld DMF. There is also provided a resistance RD and a tap RDI and resistances RC and RO with associated taps RC1,

3 RC2, "R01, and R02. The circuit is provided with power from a source, not shown, applied between the lines L-land L-.

The circuit includes va switch S which represents the command signal to the ldoory control system from all the other elevator controls, which are not shown since they "form no part of the vpresent invention. Subject 'to the "condition-jotl the' circuit shown in FIGURE l2, when the -switch S is closed-the doors vwill'clos'e and when the switchS is' open the doors'will open. It will be seen Vfrom --thecircuit that, since the'switches CS and SD are in'y the :same .lineas tl1`e`=switch S, provided that the contacts CA are open, openin-g of either of the switches CS and SD vvill, subject to the conditionfof the circuit shown in FIG- URE 2, open Ithe doors. It follows 'that'movem'ent of thestrip l'25 to the rightin FIGURE l will open the -doors by'op'ening-SD and that movement of the hall "doorto the right relative to the car 'door will also open the :doors by `opening CS.

rSince, upon `initial acceleration of 'the doors in their closing direction, itis possible that the hall door may 'lag somewhat Behind the'can'door, it is desirable to provide Vdisahling `means, to prevent operation of the switch CS until this initial acceleration is completed. "This :problem Vcould be overcome V'by increasing the "strength of spring 33 butthen too great a force Amight 'be required on the hall door to'cause the relative movement'whichwill operate the switch CS. Thecon'tacts CA therefore vare arranged' to be closed during the 'lirst few inches of the'c'zlosin'g motion A'of the `doors'from their pen'psitions and by the closing of yCA theswitch" CS vis" rendered :inoperative tocause opening of the doors for the first few inches vof closing movement,

"A'n'ormal, uninterrupted, closing sequence of the doors 'will now be described. vIn response toa closing command nfr'o'm'the other circuits of the elevator control, switch S closes causing the relay coil D to be energised through the vnormally closed switches-CS and SD. With energisation ofthe coil `D the contact D1 closes and 'the close relay C rwill be 'energised through the close 'limit contacts CL andthenorinally closedk contacts O4. yEnergisation of the relayC causes the contacts Cl'and C2 to close allowingc'urrent toilowfroin' the line L-lthrough the resistor tap RD'Lthe resistor IRD, the contacts C2, the resistor tap"RC1, the'resistor RC, the contacts O5, and the'con* v'tacts Cl to 'the negative line L-. Energisationof `the relay Cialso opens contacts Cland'CS.

Thedoor motor armature DMA is 'in parallel with -the portion of the resistor RC above the tap RC1 lso f'tharcurrent now flows through the-armature. As men- 'tioned above, the door 'motorield DMF is continuously VVelicited and therefore the door motor accelerates to a 'speed determinedlby the adjustment of the resistor taps `vRDland RCZand Vthe doors begin to close.

As the doors start to close, open check contacts OC "openbut 'with noV etfectsince resistor RO is disconnected by the now opencontacts C5. As mentioned above, the

l`sv'vitcl1'CS'rna'y'open momentarily during the initial acceleration of the doors 1but the contactsk CA are closed `tweenthe doors does take place'duringthe initial acceleration and opens switch CS, the coil D will remain energised through the contacts CA.

When the doors are a few inches from their fully `closed position,'the close check contacts CC are closed and'short'out the portion ofthe resistory RC between the taps RC1 and RC2. This reduces the voltage sup- 'plied to the door motor armature DMA which is there upon dynamically braked to a slow speed. The close limit contacts CL open when the doors are almost closed, thus vcle-energ'ising the-relay C and causing contacts CLC?. to open and contacts C4, C5 to close. The opening or" contacts C1, C2 disconnects the supply from the door motor armature DMA and the motor is dynamically braked 4 to a standstill by flow of current through the closed check contacts CC, resistor RC and contacts O5 With the doors closed, the opening sequence is as follows, switch S opens and de-energises the relay D thus opening contacts Dl and closin'gfcontacts D4. The opening of'contacts` D1 has no effect but the closing of contacts D4 energises the relay O through the open limit contacts OL and vvcontacts C4. Upon energisation of relay O, contacts Ol, O2 and O3 will close and contacts O4 and O5 will open. The closing of contacts O1 and O2 causes current to 'flow from the line L+ through the resistor tap RDI, the resistor RD, contacts Oll,`resis tor tap R01, resistor RO, contacts C5 and contacts O2 to the line L The door motor armature DMA is thus placedv in parallel -withpart of the resistor RO so that armature current ilows and the doors accelerate to a speed determined by the adjustment of the resistor taps RDI-and R01. As'the-ldoors open,the close check contacts CC open with no effect sncetheresistor RC is disconnected by now open contacts O5.

The contacts CA close when the door is a few inches from the fully open position but with no effect. The open check contacts OC then close thus shorting out the portion of the resistor y*RO between the taps R01 and R02.. The voltage applied to the motor armature DMA is thu-s reduced and the motor dynamically braked to a slow speed. When the ydoors are almost fully open, the open limit contacts OL open thus de-energising the relay O,Vthus closing contacts 'O4 and vO5 and opening the contactsl O1, O2 and O3. The opening of contacts Ol and O2 disconnects the supply `from the door motor armature DMA and the door motor is dynamically braked to -a standstill by current ilowlng through the open check contacts OC, resistor RO andjcontacts' C5.

Consider now a passenger attempting to leave the vcar while the doors are lclosing, if he presses momentarily on the strip 23 on the Vleading edge 24 of the car door the switch SDis opened. The opening of this switch SD deaenergises the relay D thusopening the contacts yDl and closing the Vcontacts -D4. The opening ofcontacts D1 de-energises the relay C thus opening contacts yCl and CZand cutting olf power from the armature DMA Vof the door motor. The de-energisation of the relay C closes the contacts C4 and the 'relay O will be energised through D4, OL and C4. Energisation of the relay O will supply openingpower for the door motor as hereinbefore described. Pressure on the strip 2li-may now be released thus allowing the relay D to become energised and opening contact D4, however current continues to vflow to relay coil O through the contactsv O3. The

doors will continue to yopen until the opening of open limit contacts OLvde-energ'ises ythe relay O thus opening the contacts O1, Q2 and -03 and .cutting cfr" power from the door motor. The doors' will now re-close immedi- -ately since the relayC is energised through the Acontacts Dl, the close limit contacts CL and the contacts O4. However, the doors,.could be held open by continuing pressure von the strip 23.

Now consider a person attempting to enter the elevator caras the doors are closing. Provided that the doors have travelled in their closing direction far enoughv for thecontacts CA to beopened, pressure on the hall .door to the right in FIGURE l will rotate the rib 29 and will open the switch CS. As the switch yCS opensthe relay D will be de-energised thus opening contacts Dlt de-energising the relay C. The closing of the contacts. C4 energises the relay O so that the'doors immediately open in the same way as if the opening had beeninitiated by the opening of -the switch SD on the cari door.

In the arrangement so far described, the rib 29 has been mounted resiliently so th'at'its mover-nent'will operate the switch CS on-` the car door. However, .it will be appreciated that a different arrangementy could Vbe used wherein the element *28 on 'the hall door couldbe 'resiliently mounted and caused tooperate aislwith ony the car door. Thus, the arrangement shown in FIGURE 1 could be modified by causing the rib 29 to be xedly mounted on the car door and resiliently mounting the element 28 on the hall door. The switch CS would be mounted on the car door as before and have an actuating arm which would coact with a projection xed to the hall door. Thus, when relative movement occurred between the doors, the switch arm would be moved by the projection to reverse the door movement in the same manner as hereinbefore described.

Moreover, the contacts CA have been described as having been operated by the door in response to a given position of the door, that is to say that the contacts CA remain closed when the hall door is within a few inches of its fully open position. However, in an alternative arrangement, a time delay mechanism could be provided whereby the contacts CA are retained closed for a predetermined time interval after the hall door has started to close. In a further arrangement the contacts CA could be operated by means which would sense the cornpletion of the initial acceleration of the doors in their closing direction.

The invention has been described with reference to an elevator car having a door which is operated by a system commonly known as single speed, side opening. However, the invention is also applicable to centre opening doors and to two speed door operations.

It will be seen that the invention provides a simple, and comparatively inexpensive means for ensuring that obstruction of the hall door will cause the doors to open.

It will be understood that the form of the invention herewith shown and described is a preferred example and that various modications may be carried out without departing from the spirit of the invention or from the scope of the appended claims.

What I claim as my invention is:

1. In an elevator system including an elevator car, a car door reversibly movable between open and closed positions, reversible power means to move said door between said positions, and a hall door reversibly movable between open and closed positions; the provision of interengaging driving elements on the car door and the hall door to move the hall door generally in synchronism with the car door; resilient mounting means for one of said elements on its associated door to bias the doors to a normal relative position and, upon obstruction of the hall door during closing, to allow further closing movement of the car door from said normal relative position and against the bias; switch means on the car door operative in response to said further closing movement of the cai door; and control means for the power means and operative in response to operation of the switch means to cause the power means to open the doors.

2. In an elevator system including an elevator car, a car door reversibly movable between open and closed positions, reversible power means to move said door between said positions, and a hall door reversibly movable between open and closed positions; the provision of interengaging driving elements on the car door and the hall door to move the hall door generally in synchronism with the car door; resilient mounting means for the element on the car door to bias the doors to a normal relative position and, upon obstruction of the hall door during closing, to allow further closing movement of the car doorfrom said normal relative position .and against the bias; switch means on the car door arranged to co-act with the element on said door and operative in response to said further closing movement of the car door; and control means for the power means and operative in response to operation of the switch means to cause the power means to open the doors.

3. In an elevator system according to claim 2, the provision of hinge means pivotally mounting the element on the car door thereto; a stop for said element; and elastic means normally urging said element against the stop, said further closing movement moving the element on the car door away from the stop and operating said switch means.

4. In an elevator system according to claim 1, the provision of disabling means to prevent operation of said switch means during the initial closing movements of the doors from their open positions.

5. In an elevator system according to claim 1, the provision of disabling means operative to prevent operation of said switch means until the closing doors have completed their initial acoelerations from their open positions.

6. In an elevator system according to claim 1, the provision of disabling means to prevent operation of said switch means for a predetermined time interval after the doors have started to close from their open positions.

7. In an elevator system according to claim 1, the provision of disabling means to prevent operation of said switch means until the doors have reached a predetermined position after leaving their open positions.

References Cited by the Examiner UNITED STATES PATENTS 2,502,995 4/ 1950 Rissler. 2,816,625 12/ 1957 McCormick. 2,985,258 5/1961 Kraft 187--52 3,050,154 8/1962 Bruns 187--52 3,063,516 11/1962 Duncan 187-52 SAMUEL F. COLEMAN, Primary Examiner.

ANDRES H. NIELSEN, Examiner, 

1. IN AN ELEVATOR SYSTEM INCLUDING AN ELEVATOR CAR, A CAR DOOR REVERSIBLY MOVABLE BETWEEN OPEN AND CLOSED POSITIONS, REVERSIBLE POWER MEANS TO MOVE SAID DOOR BETWEEN SAID POSITIONS, AND A HALL DOOR REVERSIBLY MOVABLE BETWEEN OPEN AND CLOSED POSITIONS; THE PROVISION OF INTERENGAGING DRIVING ELEMENTS ON THE CAR DOOR AND THE HALL DOOR TO MOVE THE HALL DOOR GENERALLY IN SYNCHRONISM WITH THE CAR DOOR; RESILIENT MOUNTING MEANS FOR ONE OF SAID ELEMENTS ON ITS ASSOCIATED DOOR TO BIAS THE DOORS TO A NORMAL RELATIVE POSITION AND, UPON OBSTRUCTION OF THE HALL DOOR DURING CLOSING, TO ALLOW FURTHER 